Mr. Ryutaro MORI, the present inventor once proposed a sheet-like or thin plate-like coil device (called planar inductor device), in Japanese Patent Application 2005-346039 (See Patent Document 1), suitable for inductors, transformers, non-contact type power transmission devices or the like.
The above planar inductor device provided various advantages in which a sheet-like or plate-like inductors having intended area can be designed without constraint resulted from coil characteristics, desired power can be obtained corresponding to the area when a pair of devices with the same area are placed facing each other to carry out non-contact type power transmission, and furthermore, free setting of separation cut-off lines can be introduced so that a design flexibility is much improved.
The above planar inductor device, however, had problems still unsolved even now in power transmission efficiency, unnecessary magnetic spurious radiation, unnecessary heat generation, production costs and so on when intended to produce sheet-like or thin plate-like coil devices suitable for inductors or non-contact type power transmission application systems.
Patent Document 1: WO 2007/063884 International Publication Pamphlet